For long-span composite bridges with corrugated steel webs, the encased concrete near the intermediate support section increases the weight of the girder, reduces pre-stressing efficiency, and causes difficulties in the construction process. The authors in the companion paper [1] proposed a corrugated steel web with vertical or/and horizontal stiffeners to replace or shorten the length of concrete encasement. In parallel with experimental study described in the companion paper, this paper further investigates the shear performance of proposed stiffened corrugated steel webs by numerical and analytical methods. Firstly, finite element (FE) models considering material nonlinearity, welding residual stress, and geometric imperfection were established and validated against the experimental results. Then the effects of web thickness, corrugation depth, height and thickness of stiffeners on shear strength and failure modes were analyzed based on the validated FE models. Finally, both experimental and numerical shear strength were used to evaluate the applicability of existing calculation methods proposed by different scholars to predict the shear capacity of stiffened corrugated steel web. The comparisons reveal that calculation methods proposed by Hassanein & Kharoob [2] and Leblouba et al. [3] predict the shear capacity of pure corrugated steel web more accurately, and all existing calculation methods underestimate corrugated steel web with vertical stiffeners. Therefore, the analytical model for accurately predicting shear strength of stiffened corrugated steel web need to be developed, which will be investigated in subsequent studies.@en

Diaphragm cutouts are set to release redundant constraints and hence reduce weld fatigue at the connection of U-ribs to diaphragms in orthotropic steel decks. However, most fatigue cracks which originate from the edge of cutouts are in fact detected in the diaphragms. Therefore, a retrofit technology on cracked cutouts at the diaphragm is proposed and applied to the orthotropic steel box girder of a suspension bridge. Firstly, the stress concentration on the cutout is analyzed through refined finite element analyses. Furthermore, the fatigue cracked cutouts are retrofitted by changing their geometrical parameters. Thereafter, an optimized geometry and the size of diaphragm cutouts were confirmed and applied in the rehabilitation of a suspension bridge. On-site wheel load tests were carried out before and after retrofitting of the diaphragm cutout. The stress distributions along the edges of the cutouts and at the side of a diaphragm were measured under a moving vehicle. The stress spectra at two critical locations on the edge of a cutout was obtained under longitudinally and laterally moving vehicles. Finally, the fatigue life of the cutouts is assessed by the modified nominal stress method. The analytical and test results indicate that the wheel loads on the deck transmit stress to the diaphragms through the U-ribs, during the load transmission process, the stress flow is obstructed by diaphragm cutouts, resulting in local stress concentrations around the cutouts. In addition, the overall size of the cutouts should be small, but the radius of the transition arc should be large, thus the stress flow will not be obviously obstructed. After the retrofitting of the cutouts by improved geometry, the maximum stress decreases by 87.6 MPa, which is about 40% of the original stress. The equivalent constant amplitude stress is reduced by 55.2% when the lateral position of the wheel loads is taken into consideration. Based on the stresses obtained by finite element analysis (FEA) and experimental tests, the fatigue lives of the original cutouts are 1.7 and 4.9 years, respectively, which increase to 78.1 and 155.5 years, respectively, after the cutouts were retrofitted, which indicates that the improved geometry and retrofit technology can enhance the fatigue performance and extend the fatigue life of diaphragm cutouts with fatigue cracks.@en

Composite girder with corrugated steel web is one of the promising concrete-steel hybrid structures with superior properties and cost effectiveness widely applied in highway and railway bridges. The connection between concrete slabs and corrugated steel web is an important part of such composite structure. In order to improve pouring quality and durability of concrete for joint structure between corrugated steel webs and concrete lower slab, the validity of placing lower slab on the inner side of corrugated steel webs was confirmed and a new joint structure with perforated plate connectors was proposed. Push-out tests on proposed joint structure with different parameters including the welding width and the plate thickness were carried out to study their shear strength, shear stiffness, failure modes and relative slip characteristics. Subsequently, three-dimensional finite element models taking material non-linearity and nonlinear contact between steel and concrete interface into consideration were built and validated by the push-out tests. Afterwards, parametric studies were performed to further investigate the influences of geometrical parameters (such as width, height and thickness of perforated steel plate) and material parameters including steel yielding strength and concrete compressive strength on ultimate shear strength and failure mode of the joint structure. Analytical results indicate that the shear loading capacity is increased with the thickness, the width and height of perforated plate, and the compressive strength of concrete. However, steel yielding strength, presence or absence of perforating rebar, have a negligible effect on ultimate shear strength of the joint structure. Finally, prediction equations of shear capacity were provided and compared with experimental and numerical results. The calculated shear capacity agrees well with experimental and numerical ones, indicating provided analytical equations can accurately predict shear capacity for such novel joint structure.@en

Residual stresses change the stress ratio of fluctuating stresses, hence seriously affect the fatigue life of orthotropic steel decks (OSDs) under traffic loading. Residual stress distributions near the U rib-diaphragm joints are very complicated and need to be investigated further. In this paper, a systematic method has been proposed for calculating the residual stress field in the joint of U rib and diaphragm due to thermal cutting and welding. Firstly, a mathematical model of cutting heat sources was established to predict the temperature field. Then, a numerical elastoplastic thermomechanical model was built to predict the residual stress evolutions in a diaphragm-rib joint through the whole fabrication process involving flame cutting and welding. Moreover, the simulated temperature contours at the fusion zone and the residual stress distributions in the rib-diaphragm joint were compared and verified against the experimental ones. The numerical results showed a great agreement with the experimental ones, indicating that the heat source model can be used to accurately predict the temperature field during flame cutting. Finally, the validated numerical model was utilized to conduct parametrical analyses on the effects of thermal processing rates, e.g., the cutting and welding speeds and on the residual stress distribution in the rib-diaphragm joint. The results indicate that a faster cutting speed and a slower welding speed can decrease the residual stress magnitude at the rib-diaphragm joints and reduce the high-stress zone near the diaphragm cutouts.@en

Owing to the superior mechanical performance and material efficiency, the combination of prestressed concrete (PC) slabs and corrugated steel webs (CSW) as PC girder with CSWs (PCGCSW) is extensively applied to railway and highway bridges. To overcome the shortcomings of traditional balanced cantilever construction (TBCC) of PCGCSW, reduce environmental impact, and promote sustainable construction, a novel asynchronous-pouring-construction (APC) technology is introduced in this paper. This improved method makes full use of the excellent shear capacity of the corrugated steel webs (CSWs) to support the hanging basket, increases the construction platforms to accelerate the construction speed. Based on a practical project of a long-span composite box girder bridge with CSWs in China, the construction process of the APC method is systematically introduced, and the structural safety and environmental sustainability of such bridge using APC technology are evaluated and compared with that using TBCC. The comparison results indicate that APC method can reduce the compressive stress of top concrete slab, but slightly increase the shear stress and deflection during the cantilever construction stage because the hanging basket is directly supported by CSWs. Besides, the weight of the improved handing basket in APC technology is reduced up to half in comparison that in TBCC. Accordingly, the APC technology saves a lot of energy consumption, reduces huge CO2 emissions for construction equipment, and shorts construction period. Therefore, the utilization of APRC technology can ensure the bridge's safety and reliability, effectively accelerate construction speed, reduce the construction load, decrease the environmental pollution, and save the engineering cost, which can be regarded as a sustainable and environmental-friendly construction method for composite bridges with CSWs.@en

Design optimization of fiber-reinforced polymeric (FRP) composite products is essential to facilitate their applications in engineering structures. For bridge structures, the main design optimization goals are the reduction of FRP material consumption and the structure weight, which aim to reduce the initial construction cost and achieve a longer bridge span. Compared with conventional steel–concrete composite bridges, FRP-steel composite bridges possess more design variables and more complex design process, which necessitate the simplified optimization models. This paper aims to propose a two-scale design optimation method for FRP bridge deck on the steel girder. The macro behavior of the pultruded FRP composite bridge deck is analyzed. Regarding the micro level, the equivalent properties of pultruded GFRP lamination are calculated by combining micromechanics and classical lamination theory (CLT). The above-mentioned macro pultruded GFRP bridge level and the micro fiber/resin level were bridged based on the assumption that the micro-component effective homogenized strain equals to the corresponding macro strain. The two-scale lamination optimization of pultruded GFRP bridge deck is finally achieved by finding optimized two-scale design variables that can achieve the minimum bridge weight or the lowest initial construction cost with all listed constraint requirements satisfied. A pultruded FRP deck supported on equally-spaced steel girders was selected as a case study to show how to obtain the optimized two-scale parameters by using this proposed optimization method. The optimized results of the top flange thickness, tu, the bottom flange thickness, tl, the web height, hw, and the web thickness per meter, tw, are 46.02 mm, 45.86 mm, 300.0 mm and 37.42 mm, respectively. Results also showed that the optimized ratio of the 0°-lamina, 45°-lamina, and the 90°-lamina are77.9%, 17.1%, 5.0%. The optimized fiber volume fraction is 65.2%.@en

In this paper, analytical and numerical homogenization methods are proposed to effectively simulate the macroscopic characteristics of a pultruded composite lamina. A continuum damage model was implemented via user material subroutine to model fiber failure, while the Mohr-Coulomb plastic criterion is employed to model matrix damage. In order to simulate the damage of the fiber-matrix interface, the relationship between traction and displacement is established. The proposed theoretical and numerical models were verified by tensile, compressive, and shear test results. The outcomes of this study indicated that both theoretical, numerical prediction values agree well with experimental verification results confirming the validity of the proposed methodology in providing a reliable reference for structural design of pultruded fiber reinforced polymeric (FRP) composite structures.@en

Steel-concrete composite high bridge pier has been applied increasingly in China and around the world. Most applied steel type in the composite piers are H-shaped steel and steel pipe, while seldom research or practice is associated with angle steel. This paper conducted parametric study on the composite column with equal-leg angle steel and aimed to investigate the ultimate load and displacement ductility of the composite columns with different parameters. The parameters include the type of shear connector (stud and perfobond connectors), the type of structural steel (H-shaped steel and angle steel), steel-plate hooping ratio, shear-span ratio, and axial compression ratio. Finite element analysis was conducted for each specimen, which incorporated the concrete confinement effect, as well as the inelastic behavior of concrete, structural steel, and longitudinal and transverse steel bars. The equal-leg angle steel composite column was found to have slightly higher strength and displacement ductility than H-shaped steel composite column. The increase of steel-plate hooping result in larger strength and displacement ductility for the composite column, and the increase of shear-span ratio and axial compression ratio decrease the displacement ductility. Research results suggest stud and perfobond shear connectors should be applied as axial compression ratio being larger than 0.2 and 0.3, respectively. This paper provides reference for research and engineering practice of the concrete encased angle steel composite columns and bridge piers.@en

The prestressed concrete girder with corrugated steel webs is one of the most promising steel-concrete hybrid structures applied to highway and railway bridges, owing to its excellent mechanical properties and efficient material utilisation. Composite bridges with corrugated steel webs (CBCSWs) have undergone rapid development in China since 2005, resulting in remarkable technical progress in many aspects. A state-of-the-art review of CBCSWs in China is presented. Based on data collected for over 90 CBCSWs built in China during the years 2005-2018, characteristics relating to bridge span, structural type and construction methods are comprehensively analysed. Some mechanical issues regarding the design and construction of typical CBCSWs are elaborated to understand fully their structural performance and promote their development. Furthermore, a few representative CBCSWs are expounded in relation to their innovative structural design and construction techniques; their respective characteristics are highlighted. Finally, several conclusions are drawn and future research directions are predicted: the CBCSW is a competitive bridge solution when 80-200 m main spans are required; advanced materials, innovative structure types and advanced construction methods making good use of corrugated steel web are the source of its development. The experiences in this study can serve as a useful base for constructing more excellent and impressive CBCSWs.@en

Steel-concrete composite structures have been extensively used in building, bridges, and other civil engineering infrastructure. Shear stud connectors between steel and concrete are essential in composite members to guarantee the effectiveness of their behavior in terms of strength and deformability. This study focuses on investigating the shear stiffness of headed studs embedded in several types of concrete with wide range of compressive strength, and their effects on the elastic behavior of steel-concrete composite girders were evaluated. Firstly, totally 206 monotonic push-out tests from the literature were reviewed to investigate the shear stiffness of headed studs embedded in various types of concrete (NC, HPC, UHPC etc.). Shear stiffness of studs is defined as the secant stiffness of the load-slip curve at 0.5Vu, and a formulation for predicting defined shear stiffness in elastic state was proposed, indicating that the stud diameter and the elastic modulus of steel and concrete are the main factors. And the shear stiffness predicted by the new formula agree well with test results for studs with a diameter ranging from 10 to 30 mm in the concrete with compressive strength ranging from 22.0 to 200.0MPa. Then, the effects of shear stiffness on the elastic behaviors of composite girders with different sizes and under different loading conditions were analyzed, the equations for calculating the stress and deformation of simply supported composite girders considering the influence of connection's shear stiffness were derived under different loading conditions using classical linear partial-interaction theory. As the increasing of shear stiffness, the stress and deflection at the most unfavorable section under partial connected condition tend to be those under full connected condition, but the approaching speed decreases gradually. Finally, the connector's shear stiffness was recommended for fully connection in composite girders with different dimensions under different loading conditions. The findings from present study may provide a reference for the prediction of shear stiffness for headed studs and the elastic design of steel-concrete composite girder.@en

This paper proposes an innovative use of corrugated steel plates as the webs of the crossbeam in the tower of a suspension bridge to get better seismic performance. Three 1/4-scaled models of composite beam with corrugated steel webs considering different shear-span ratio were fabricated to conduct quasi-static test. The structural behaviors including failure modes, hysteretic curves, ductility, strength and stiffness degradation, energy dissipation capacity, deformation recovery ability, shear force distribution and strain responses were investigated. Test results indicate that the specimen with large shear-span ratio presents ductile flexural failure, and the hysteretic curve is stable and plump with slight pinching, which indicates good energy dissipation performance. However, the specimen with small shear-span ratio fails due to brittle shear buckling of corrugated steel web, showing remarkable pinching phenomenon and poor hysteretic behavior. With the increase of shear-span ratio, the load-carrying capacity and lateral initial stiffness are reduced, but the ductility and energy dissipation ability are improved significantly. The energy dissipation capacity of such composite beam is better than that of the RC structures, the strength degradation is slight for the specimen with a proper shear-span ratio, and the deformation recovery ability is good for all test specimens. The corrugated steel web carries about 80% of the shear force and shear stress uniformly distributed along the web height. The test results demonstrate that the composite beam with corrugated steel web of a reasonable shear-span ratio can be applied in anti-seismic structure with superior energy dissipation performance. In addition, simplified formulas were proposed to evaluate the flexural strength and shear buckling strength of a composite beam with corrugated steel webs, the calculated results agree well with the test results, verifying the accuracy of these proposed formulas.@en

We present an innovative prefabricated composite box girder with corrugated webs and concrete-filled steel tube slab to prevent cracking in the web and reduce the self-weight, which is suitable for long-span structures. We carried out systematic experimental and analytical studies to investigate the structural performance, including the loading capacity and dynamic properties of a prefabricated composite box girder bridge before and after erection. Firstly, we tested a prefabricated composite girder with a single box section before erection under monotonic loading, measuring vertical deformation, flexural strain on the slabs, and shear strain on the corrugated steel webs, and evaluating the load-carrying capacity and stiffness reduction. Secondly, we conducted field live-load tests, including a calibration test and a dynamic test, on a composite bridge with twin prefabricated box girders. We hired four-axle heavy trucks for a calibration test to explore the static responses in terms of displacement, bending strain on the slabs, and shear strain on the corrugated steel webs. In the dynamic tests, we carried out a modal test using ambient vibration method and a moving load test in order to determine the dynamic behavior, which involves natural frequencies, the mode shapes, and the dynamic load factor (DLF). Based on the test results, the structural performance was evaluated by the AASHTO bridge rating process. All the findings from the load-carrying capacity test at ultimate state, calibration and dynamic load tests at service state in this study may provide a reference for the design and construction of such type of bridges.@en

Basalt fiber reinforced concrete (BFRC) has been widely utilized in various constructions such as buildings, large industrial floors, and highways, due to its excellent physical and mechanical properties, as well as low production cost. In order to address the influence of basic parameters such as fiber volume fraction (0.05∼0.40%), fiber length (12∼36 mm) of BF, and compressive strength (30, 40, and 50 MPa) of concrete on both physical and mechanical properties of BFRC including compressive strength, tensile and flexural strength, workability, and anti-dry-shrinkage cracking properties, a series of standard material tests were conducted. Experimental results indicated that clumping of fibers may occur at relatively higher fiber volume fraction resulting in mixing and casting problems. Based on experimental values of mechanical properties and anti-dry-shrinkage cracking resistance of BFRC, the reasonable basalt fiber length and fiber volume fractions are identified. The addition of a small amount of short basalt fibers can result in a considerable increase in both compressive strength and modulus of rupture (MoR) of BFRC and that the proposed fiber length and content are 12.0 mm and 0.10%∼0.15%, respectively. As the length of basalt fibers increases, the development of early shrinkage cracks decreases initially and then increases slowly and the optimal fiber length is 18.0 mm. Results of the study also indicated that early shrinkage cracks decrease with the increase of fiber volume fraction, and when the volume fraction of 0.20% is used, no cracks were observed. All the findings of the present study may provide reference for the material proportion design of BFRC.@en

In this study, flexural behaviors of the pultruded composite laminate were evaluated through experiments and theoretical analysis. Three-point flexural tests were performed for pultruded specimens. The typical failure mode for the longitudinal flexural specimens was local crush on the top surface accompanied with local cracks on the bottom surface at midspan. For the transverse tests, the specimens presented a failure pattern with local cracks initiated and propagated at both the top and bottom sides at the midspan. Theoretical analysis, based on micromechanics and macromechanics, was performed to predict flexural deformation and stress distribution of the pultruded laminate beam. Based on the continuum damage model proposed by the authors, this paper mainly investigates the flexural behavior and failure pattern of pultruded lamination. The theoretical and finite element results agreed well with the test results. The results can provide a reference for the design of the structural pultruded modular systems.@en

In this study, a methodology proposing size reduction of flat steel bearing plates that are commonly used in experimentally evaluating composite deck to transfer and distribute simulated vehicles loads to the top of bridge deck specimens is presented. The proposed methodology considers the tire-to-deck effects based on both a contact pressure distribution model and finite element (FE) simulation results. Ultimate capacity and associated failure modes for the following two loading cases: (i) moment-dominated, and (ii) moment-shear coupled loads were experimentally evaluated. Experimental results showed that the ultimate capacity for moment-dominated loading case is 35.60 kN, while capacity for the same composite deck when subjected to a moment-shear coupled load is 44.34 kN. Experimental results indicated that the initiation of failure for both loading cases was in the form of the development of longitudinal cracks at both top flanges and at outer web section near the loading side. Finite element models that consider lamina damage were developed and analyzed. A good agreement between numerical and experimental results is achieved.@en